In a number of applications, it is desirable to provide laminated products with a detachable window or flap. As used herein, the term "laminated" includes products formed from layers of materials adhesively interconnected, e.g., by mounting or other laminating technique. For example, display devices, such as point-of-purchase paperboard displays, may conveniently be provided with fold-out, easel flaps to support the display devices in an inclined position. In this manner, display devices can be shipped and stored in a substantially planar configuration and then the flaps can be deployed so that the devices are self-standing. Similarly, cardboard game pieces, for use in promotional sweepstakes, can have pop-out windows which a contestant removes to reveal prize information. In addition, packages such as cardboard boxes may have a flap which folds out to form or provide access to a spout to facilitate pouring of the package contents. Many other examples of laminated products having a window or flap are possible.
A problem associated with such products is that the process for producing the products is typically relatively complex, time-consuming and expensive. The case of paperboard display devices having fold-out easel flaps is illustrative. Such devices are commonly constructed from front and rear panels which are adhesively interconnected, e.g., by applying glue therebetween, to form the display device. Often, the front panel has a forwardly facing display surface and the rear panel includes an easel flap which can be deployed by folding the flap rearwardly to provide support. Alternatively, an easel may be formed separately and adhesively attached to the display device. As is readily appreciated, it is desirable to avoid adhesive attachment of the flap to adjacent portions of the display device so that the flaps can be easily deployed.
One known process for producing such paperboard display devices involves applying an adhesive across the extent of the interface between front and rear panels, wherein the rear panel includes a detachable easel flap, except for that portion of the interface where the easel flap is located. Accordingly, glue can be applied to portions of the rear panel around the easel flap in a pattern which complements the shape of the easel flap. Because glues are often tacky and highly viscous and therefore are poorly suited for certain high speed application techniques such as lithographic printing, the glue is commonly applied by silk-screening or a similar relatively slow and labor intensive process, thereby limiting production output and increasing production costs. Silk screening processes also result in usage of relatively large quantities of glue, further increasing production costs.
Manually coating panels with an adhesive by a process such as described above typically results in coating rates below about 120 panels per labor hour. Machines have been developed to mechanize the above-described process, including a machine known as the Automatan manufactured by Mirus Co. However, such machines are typically relatively expensive and are usually dedicated to particular coating applications, thereby increasing costs.